Earth as an Ecosystem

Reactions in which an atoms nucleus splits into smaller parts (and 2/3 neutrons) releasing a large amount of energy in the process. It can be spontaneous, or occur when the nucleus of a heavy atom captures a neutron

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Define nuclear reaction

when neutrons released from fission produce an additional fission in at least on other nucleus, which in turn produces neutrons etc.

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Give two ways that n's can be lost?

1) leaving into other surroundings 2) neutron capture by other nuclides e.g. 238U

coolants (absorb heat from fission reaction and transport from core to turbine), moderators (slows neutrons by causing to collide) and control rods (shuts down nuclear fission process when required by absorbing ALL neutrons)

In a large steel building with a hemispherical dome- capable of withstanding high pressures.

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How is the internal pressure of fission reactors controlled?

spray system, fan cooler system, ice condenser system

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Define nuclear fusion

The reaction in which two or more atomic nuclei collide at very high energy and join to form a new nucleus

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Why is nuclear fusion so much more difficult to achieve than nuclear fission?

fusion can only occur by the collision of positively charged nuclei. Therefore, to overcome electrostatic repulsion, extremely high energy particles are required (100 million K). Contrast to fission which absorbs neutral neutrons= much easier

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Give the chemical equation for the fusion reaction that requires the lowest ignition temperature

Li+D --> 2He + 22.4MeV

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Where does deuterium come from? What % of naturally occurring H does this make up?